There are numerous materials which are commonly used as countertop materials in kitchens around the world. These materials include laminate, wood, sheet metal, tile, and stone. Looking back to at least the 1940's, the popularity of laminate for countertops can hardly be disputed. The popularity of laminate as a countertop material remained strong at least through the 1990's. However laminate has its drawbacks inv that it is susceptible to chipping, scratching, melting and de-laminating. In the 1960's, Corian® was developed and introduced to consumers. Corian® is a solid surface material similar to stone, however it is still susceptible to scratches and discoloration.
Beginning in the late 1990's, the availability of less expensive computer numerically controlled (CNC) saws allowed granite to become much more affordable for middle-class households. After measurements are taken regarding the dimensions of a desired countertop, those measurements are exported into a computer which cuts the slab to exacting specifications including cut-outs for sinks, faucets and fixtures. After the slab is polished, it is then ready to be installed by a skilled installer.
One drawback of stone countertops is their weight. A large stone slab intended for a cabinet or island in a homeowner's kitchen may weigh several hundred pounds. Most facilities where stone countertops are produced have one or more the crane lifts to aid in moving the slab from place to another. These lifts are used to load the slab on to or within a truck to deliver to a customer. However, once on site, the lifts are no longer available and the slabs must be transported within a building or dwelling by hand. Over the years numerous styles of carts have been used to move stone slabs from a vehicle to the inside of a building. One major drawback of these carts is that they are unstable and they require two or more people to operate and move the slab. Examples of these devices include:
U.S. Pat. No. 8,348,287 discloses a slab cart for sheet material which includes a dolly component; shelf component; and a mechanism for coupling the shelf component to the dolly component in a pivotable manner, so that the shelf component will go from a horizontal position to a vertical position. When shelf component is in the horizontal position, the sheet material may be slid off of the shelf component onto a support table or be manually slid from the support table onto the shelf component by a person using the slab cart. When the shelf component with the sheet material is in the vertical position, the sheet material will be held on edge to the shelf component and be transported by dolly component through the confines of narrow places. However, '287 does not disclose the inclusion of a lift mechanism operationally associated with the castor frame, the upright members and the platform frame wherein the lift mechanism may raise or lower said platform frame relative to the castor frame.
U.S. Pat. No. 5,460,469 discloses a panel loading and handling apparatus having a U shaped, horizontal frame with rollers mounted along the bottom. A pair of rods with hooks at their bottoms are mounted on rollers in the channels to roll up and down the channels. A cable winding apparatus is provided on one of the channels for winding a cable attached to the rods to raise the rods with the hooks at their bottom upward, simultaneously, along the channels to raise a drywall panel mounted thereon. The Support frame is adapted to be mounted on the rollers high enough off the ground to enable the base legs of a drywall panel lifter to roll underneath the frame to close proximity to the apparatus, and the hooks are adapted to be raised high enough in relation to lifting means on the lifter, so that the panel can be lifted by the hooks and, by the apparatus being in close proximity to the lifter having extended height lifting capability, can be transferred onto the lifting means of the lifter and lifted by the lifting means to an extended height. However, '469 is designed for use in drywall installation which is much lighter than stone slabs and lacks the ability to be used by a single person to install heavy countertops.
In light of all of the inadequacies with existing slab carts above, it is clear that a need exists to provide a device which aids an installer with the transportation and installation of countertops.